Dosimetric Characterization of Small Radiotherapy Electron Beams Collimated by Circular Applicators with the New Microsilicon Detector

High-energy small electron beams, generated by linear accelerators, are used for radiotherapy of localized superficial tumours. The aim of the present study is to assess the dosimetric performance under small radiation therapy electron beams of the novel PTW microSilicon detector compared to other available dosimeters. Relative dose measurements of circular fields with 20, 30, 40, and 50 mm aperture diameters were performed for electron beams generated by an Elekta Synergy linac, with energy between 4 and 12 MeV. Percentage depth dose, transverse profiles, and output factors, normalized to the 10 × 10 cm2 reference field, were measured. All dosimetric data were collected in a PTW MP3 motorized water phantom, at SSD of 100 cm, by using the novel PTW microSilicon detector. The PTW diode E and the PTW microDiamond were also used in all beam apertures for benchmarking. Data for the biggest field size were also measured by the PTW Advanced Markus ionization chamber. Measurements performed by the microSilicon are in good agreement with the reference values for all the tubular applicators and beam energies within the stated uncertainties. This confirms the reliability of the microSilicon detector for relative dosimetry of small radiation therapy electron beams collimated by circular applicators.

An algorithmic approach to entanglement-assisted quantum error-correcting codes from the Hermitian curve

<p style='text-indent:20px;'>We study entanglement-assisted quantum error-correcting codes (EAQECCs) arising from classical one-point algebraic geometry codes from the Hermitian curve with respect to the Hermitian inner product. Their only unknown parameter is <inline-formula><tex-math id="M1">\begin{document}$ c $\end{document}</tex-math></inline-formula>, the number of required maximally entangled quantum states since the Hermitian dual of an AG code is unknown. In this article, we present an efficient algorithmic approach for computing <inline-formula><tex-math id="M2">\begin{document}$ c $\end{document}</tex-math></inline-formula> for this family of EAQECCs. As a result, this algorithm allows us to provide EAQECCs with excellent parameters over any field size.</p>

Automated Functional Color Field Tester (FCFTester) Trends and Reproducibility – A Multicenter Pilot Study

Background: The present study was designed to assess a protocol for investigating normative trends of kinetic color visual field sizes and reproducibility of such utilizing the Automated Functional Color Field Tester (FCFTester). Methods: The participants were recruited at three clinical sites. The participants were screened for the study based on a questionnaire designed by the authors to help assess the inclusion and exclusion criteria. There were 116 adult-only participants, however, only those reporting White race (n = 106) were used for statistical analysis. The mean age was 35.8 (std = 14) and nearly 70% of the sample was female. Results: This study demonstrated that kinetic visual field sizes across all four color isopters are not influenced by gender (p = 0.96) nor eye tested (p = 0.46). Only a slight difference in mean visual field sizes was found between the three clinical sites ranging from less than 2.5 degrees when the target was blue or green to less than 1.5 degrees for white or red targets. Overall, age had limited, yet significant, influence on kinetic field sizes likely related to the relatively young age of our participants. A significant difference in mean field size existed when comparing the four color isopters with an ascending order of green, red, blue, and white. This pattern was consistent across the three testing sites. Variability in field size for each color isopter was slight across the three clinical sites. Conclusion: The present pilot study shows promise that a protocol can be established to provide reproducible data and normative trends in kinetic color visual field testing. The authors recognize that this should be achievable with further refinement of the current testing protocol.

Dosimetric Characterization of Small Radiation Therapy Electron Beams Collimated by Tubular Applicators With the New Micro-Silicon Detector

High-energy small electron beams generated by linear accelerators are used for radiotherapy of localized superficial tumors. The aim of the present study is to assess the dosimetric performance under small radiation therapy electron beams of the novel PTW microSilicon detector by comparison with commercially available dosimeters. Relative dose measurements of circular fields with 20, 30, 40 and 50 mm aperture diameters were performed for 4 to 12 MeV energy range of electron beams generated by an Elekta Synergy linac. Percentage depth dose, transverse profiles and output factors normalized to the 10 &times; 10 cm2 reference field were measured. All dosimetric data were collected in a PTW MP3 motorized water phantom at SSD of 100cm by using the novel PTW microSilicon detector. The PTW diode E and the PTW microDiamond were also used in all beam aperture for benchmarking. Data for the biggest field size were also measured by the PTW Advanced Markus ionization chamber.Measurements performed by the microSilicon are in good agreement with the reference values for all the tubular applicators and beam energies, within the stated uncertainties. This confirms the reliability of the microSilicon detector for relative dosimetry of small radiation therapy electron beams collimated by tubular applicators.

Changes in Receptive Field Size in Syngap1 +/- Mouse Model of Autism Spectrum Disorder

Background and Hypothesis: Autism spectrum disorder (ASD) is a form of intellectual disability with impairments in social functioning and cognition. Mutations within the SynGAP1 gene are associated with ASD due to over activation of RAS-GTP causing insertion of AMPA receptors onto the post synaptic membrane, and thus early maturation of dendrites. These mutations lead to an excitatory/inhibitory imbalance within the brain, and patients often present with intellectual disability, seizures, and issues of cognition. Research has shown that Syngap1 +/- mice have decreased cortical gray matter brain volume throughout areas involved in the visual system pathway. However, hierarchal visual processing has not been well characterized in a Syngap1 +/- mouse model of autism. Project Methods: Using 64 and 128 channel microelectrodes, we recorded the neural activity within V1 of four mice. Neural activity was recorded in response to visual stimuli - testing receptive field size between two wild-type and two Syngap1 +/- mice. Data was run through spike sorting algorithms to identify neurons. Receptive field area for each neuron was then calculated and compared between the two genotypes. Results: The receptive field areas of Syngap1 +/- mice were statistically larger (p < 0.01) compared to wild type mice. Syngap1 +/- mice had a mean receptive field area of 450.5 visual degrees (±443.7) and WT mice had a mean receptive field area of 261.1 visual degrees (±187.21). Most of the neurons within Syngap +/- had no distinct receptive field, 67.9%, while only 25.7% of wild type neurons lacked a distinct receptive field. Conclusion and Potential Impact: Overall, Syngap1 +/- mice had larger, and less distinct receptive fields compared to wild type mice. Deficiencies in the Syngap1 protein may impair refinement of visual stimuli. Understanding the mechanism of response of missing SynGAP1 can inform directed therapies and interventions to treat patients with the missing gene and manage their intellectual disability.

Electron Beam Measurements Employing Electron Montecarlo Algorithm on TrueBeam STx® and Clinac iX® Linear Accelerators

Electron beam measurement comparison between TrueBeam STx® and Clinac iX® established. Data evaluation of eMC-calculated and measured for TrueBeam STx® performed. Dosimetric parameters measured including depth dose curves for each applicator, percentage depth dose (PDDs) curves without applicator, the profile in-air for a large field size 40×40 cm2, and the Absolute Dose (cGy/MU) for each applicator using a large water phantom (PTW, Freiburg, Germany), employing Roos and Markus plane-parallel ionization chambers. The data were examined for five electron beams of Varian’s TrueBeam STx® and Clinac iX® machines. A comparison between measurement PDDs and calculated by the Eclipse electron Monte Carlo (eMC) algorithm was performed to validate Truebeam STx® commissioning. The measured data indicated that electron beam PDDs from the TrueBeam STx® machine are well matched to those from Clinac iX® machine. The quality index R50 for applicator 15×15 cm2 was in the tolerance intervals. However, Surface dose (Ds) increases with increasing energy for both accelerators. Comparisons between the measured and eMC-calculated values revealed that the R100, R90, R80, and R50 values mostly agree within 5 mm. Measured and calculated bremsstrahlung tail Rp correlates well statistically. Ds agrees mostly within 2%. Electron beams were successfully validated for TrueBeam STx®, a good agreement between modeled and measured data was observed.

Profitability of Crop Cultivation in Small Arable Fields When Taking Economic Values of Ecosystem Services into Account

Small arable fields are beneficial with regard to ecosystem services, e.g., concerning biodiversity. By selecting appropriate crops and cultivation practices, arable fields can also be used as carbon sinks. The objectives of this study were to investigate what impact field conditions (e.g., field size and shape) and payments (subsidies) for environmental benefits have on profitability. A dynamic simulation model was used to simulate machine operations in fields of two different shapes and five different sizes (from 0.75 to 12.00 ha). A wide range of crops cultivated in Sweden were investigated (fallow land and plantation of Norway spruce were also included). A perimeter-based subsidy was suggested in order to conserve and promote biodiversity, and an area- and crop-based subsidy was suggested in order to promote sequestration of soil organic carbon (SOC). The results showed that, without financial support and from a purely economic point of view, most field types investigated should be planted with Norway spruce. With currently available subsidies, e.g., EU Common Agricultural Policy (CAP) direct payments, hybrid aspen, poplar, fallow, and extensive ley cultivation are the most profitable crops. Perimeter-based subsidies favoured the net gain for small fields. As expected, a subsidy for sequestration of SOC favoured cultivation of specific SOC-sequestering crops such as ley, willow, and poplar. Our recommendation for future studies is to investigate a well-balanced combination of perimeter-based support and SOC sequestration support that benefits biodiversity and climate under different cultivation conditions.

Measurement and Characterisation of a Diffuse Acoustic Field Using a Phased Array

A diffuse acoustic field has been increasingly used to infer temporal changes in the structures, such as early dislocations and microcracking. This study explores three different techniques to characterise acoustic field by using a single ultrasonic phased array. The first two techniques are proposed to measure spatial uniformity of wave field by examining differences in the integral of energy and the maximum energy respectively at multiple inspection locations. The third one is developed to evaluate the degree of phase coherence between propagating waves transmitted sequentially by two neighbouring array elements. The efficacy of these techniques are investigated by examining their metrics on simulations and well-known samples. The results suggest that two selected metrics can be used to quantitatively estimate the diffuse field start time as well as the field size by comparing their value with the idealised diffuse state (15% for the energy integral metric, ηarea and 1 for the phase coherence metric, ηphase) and identifying the convergence start point.